Provide LICENSE file

[jake-scott]

We run a proxy (Artifactory) that checks that modules it downloads have an acceptable license. It is currently blocking your fantastic modules because it can't find a valid license file.

Would it be possible to add a LICENSE file to the distribution (I guess a copy of the MIT license?) to unblock these kinds of issues?

[vikstrous2]

Also, the go docs are not displayed due to not having a license file https://pkg.go.dev/github.com/soniakeys/graph?utm_source=godoc